Can you change the Serial Number on digital downloaded version EA manager?

I bought a new copy of 2142 on the EA download manager and as i got to the check out and payed for the
2142 deluxe addition i got a message saying Sorry only one copy of BF2142 per Email address, you
see i had a copy on the Email address i used, so anyway to my point, after receiving the message
saying i would not be charged i still got an Email from EA giving me Serial Number so could this be used by
someone else?